1Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
2Department of Medical Device Management and Research, Samsung Advanced Institute for Health Science & Technology, Sungkyunkwan University, Seoul, Korea
3Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Korea
4Institute of Advanced Convergence Technology, Kyungpook National University, Daegu, Korea
Copyright © 2021 by the Korean Cancer Association
This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Ethical Statement
The institutional review board at Samsung Medical Center (file no. SMC 2020-02-134-001, April 2, 2020). Informed consent was waived.
Author Contributions
Conceived and designed the analysis: Ju SG, Ahn YC.
Collected the data: Kim YB, Park SG, Na CH, Choi YM, Hong CS, Oh D, Kwon DY, Kim CC, Kim DH.
Performed the analysis: Kim YB, Park SG, Na CH, Choi YM, Hong CS, Oh D, Kwon DY, Kim CC, Kim DH.
Wrote the paper: Ju SG, Ahn YC.
Conflicts of Interest
Yong Chan Ahn, a contributing editor of the Cancer Research and Treatment, was not involved in the editorial evaluation or decision to publish this article. All remaining authors have declared no conflicts of interest.
Priority | Structure | Constraints |
---|---|---|
1 | P-GTV |
D95 ≥ 67.2 Gy (100%) D99 ≥ 95% of the prescribed dose (67.2 Gy) V73.9 (110%) ≤ 1 cm3 |
P-CTV |
D95 ≥ 56.0 Gy (100%) D99 ≥ 95% of the prescribed dose (56.0 Gy [100%]) |
|
P-corda) | Dmax ≤ 45.0 Gy | |
2 | Parotid | Dmean < 26.0 Gy |
3 | M-tongue and M-OC/OP |
Dmean < 30.0 Gy V30 < 30% |
4 | Brain stem | Dmax ≤ 54.0 Gy |
Dmax, maximum dose; Dmean, mean dose; DV, D dose delivered to V% of organ volume; M-OC/OP, mucosa of the oral cavity and oropharynx; M-tongue, mucosa of the tongue; P-cord, planning spinal cord; P-CTV, planning clinical target volume; P-GTV, planning gross target volume; VD, absolute or percentage of organ volume receiving D Gy or higher.
a) P-cord means the planning volume for the spinal cord which was generated by adding 3–5 mm margin to the actual spinal cord.
Parameter | M-Tongue | M-OC/OP | ||||
---|---|---|---|---|---|---|
|
|
|||||
SMP | SCTID | p-value | SMP | SCTID | p-value | |
Volume (cm3) | 15.4±1.8 | 18.5±1.4 | 0.001a) | 43.8±9.0 | 46.3±17.3 | 0.659 |
|
||||||
V15 (%) | 79.0±10.2 | 55.1±11.7 | 0.001a) | 79.3±7.9 | 77.4±6.6 | 0.482 |
|
||||||
V30 (%) | 38.1±10.6 | 22.2±9.2 | 0.001a) | 49.7±9.8 | 46.9±9.6 | 0.359 |
|
||||||
V45 (%) | 16.1±10.8 | 6.1±5.3 | 0.001a) | 27.3±10.2 | 21.7±8.6 | 0.035a) |
|
||||||
V60 (%) | 1.0±1.1 | 0.3±0.9 | 0.074 | 8.8±6.6 | 5.3±5.0 | 0.012a) |
|
||||||
Dmean (Gy) | 27.8±4.1 | 20.7±3.2 | 0.001a) | 32.4±4.5 | 30.5±3.7 | 0.105 |
|
||||||
Dmax (Gy) | 60.1±5.9 | 56.6±6.0 | 0.037a) | 67.4±2.3 | 65.6±3.3 | 0.005a) |
Values are presented as mean±standard deviation. Dmax, maximum dose; Dmean, mean dose, M-OC/OP, the mucosa of the oral cavity and oropharynx; M-tongue, mucosa of the tongue; SCTID, semi-customized tongue immobilization device; SMP, standard mouthpiece; VD (15, 30, 45, and 60), the percentage of the tongue volume that received D (15, 30, 45, and 60) Gy or more.
a) Statistically significant.
Parameter | SMP | SCTID | p-value |
---|---|---|---|
P-GTV | |||
D2% (Gy) | 68.7±0.5 | 68.9±0.6 | 0.087 |
D98% (Gy) | 66.4±0.2 | 66.2±0.2 | 0.005a) |
D50% (Gy) | 67.7±0.4 | 67.7±0.3 | 0.619 |
HI | 0.035±0.1 | 0.039±0.1 | 0.011a) |
CI | 0.7±0.1 | 0.7±0.1 | 0.380 |
P-CTV | |||
D2% (Gy) | 68.3±0.4 | 68.4±0.4 | 0.570 |
D98% (Gy) | 58.5±2.2 | 58.4±2.5 | 0.430 |
D50% (Gy) | 62.9±2.4 | 62.9±2.6 | 0.912 |
HI | 0.2±0.1 | 0.2±0.1 | 0.286 |
CI | 0.8±0.1 | 0.8±0.1 | 0.742 |
Parotid glands | |||
Dmean (Gy) | 30.8±3.9 | 30.7±3.0 | 0.779 |
P-cord | |||
Dmax (Gy) | 30.6±4.9 | 30.5±7.4 | 0.973 |
Brainstem | |||
Dmax (Gy) | 40.8±12.7 | 40.2±11.6 | 0.624 |
Values are presented as mean±standard deviation. CI, conformity index; Dmax, maximum dose, Dmean, mean dose; DV%, minimum dose received by 2% (D2%), 98% (D98%), and 50% (D50%) of the PTVs; HI, homogeneity index; OARs, organ at risks; P-cord, planning spinal cord; P-CTV, planning clinical target volume; P-GTV, planning gross target volume; SCTID, semi-customized tongue immobilization device; SMP, standard mouthpiece.
a) Statistically significant.
Patients’ characteristics
Case No. | Sex | Age (yr) | Primary site | Clinical stage | Pathology | Aim of RT |
---|---|---|---|---|---|---|
1 | Male | 62 | NPX | cT1N3M0 | Squamous, NOS | Definitive CCRT |
2 | Male | 61 | NPX | cT1N2M0 | Squamous carcinoma | Definitive CCRT |
3 | Male | 50 | NPX | cT3N3M0 | Squamous carcinoma | Definitive CCRT |
4 | Female | 39 | NPX | cT2N3bM0 | Squamous carcinoma | Definitive CCRT |
5 | Female | 52 | NPX | cT3N3M0 | Squamous carcinoma | Definitive CCRT |
6 | Male | 55 | NPX | cT1N1M0 | Squamous carcinoma | Definitive CCRT |
7 | Male | 62 | NPX | cT1N2M0 | Undifferentiated carcinoma | Definitive CCRT |
8 | Male | 46 | NPX | cT1N0M0 | Undifferentiated carcinoma | Definitive RT alone |
9 | Male | 43 | NPX | cT3N3M0 | Undifferentiated carcinoma | Definitive CCRT |
10 | Male | 51 | NPX | cT3N2M0 | Squamous carcinoma | Definitive CCRT |
CCRT, concurrent chemoradiation therapy; NOS, not otherwise indicated; NPX, nasopharynx; RT, radiation therapy.
Dose constraints for inverse planning
Priority | Structure | Constraints |
---|---|---|
1 | P-GTV | D95 ≥ 67.2 Gy (100%) D99 ≥ 95% of the prescribed dose (67.2 Gy) V73.9 (110%) ≤ 1 cm3 |
P-CTV | D95 ≥ 56.0 Gy (100%) D99 ≥ 95% of the prescribed dose (56.0 Gy [100%]) | |
P-cord |
Dmax ≤ 45.0 Gy | |
2 | Parotid | Dmean < 26.0 Gy |
3 | M-tongue and M-OC/OP | Dmean < 30.0 Gy V30 < 30% |
4 | Brain stem | Dmax ≤ 54.0 Gy |
Dmax, maximum dose; Dmean, mean dose; DV, D dose delivered to V% of organ volume; M-OC/OP, mucosa of the oral cavity and oropharynx; M-tongue, mucosa of the tongue; P-cord, planning spinal cord; P-CTV, planning clinical target volume; P-GTV, planning gross target volume; VD, absolute or percentage of organ volume receiving D Gy or higher.
a)P-cord means the planning volume for the spinal cord which was generated by adding 3–5 mm margin to the actual spinal cord.
Comparison of geometric and dosimetric characteristics between the SMP and the SCTID
Parameter | M-Tongue | M-OC/OP | ||||
---|---|---|---|---|---|---|
|
| |||||
SMP | SCTID | p-value | SMP | SCTID | p-value | |
Volume (cm3) | 15.4±1.8 | 18.5±1.4 | 0.001 |
43.8±9.0 | 46.3±17.3 | 0.659 |
| ||||||
V15 (%) | 79.0±10.2 | 55.1±11.7 | 0.001 |
79.3±7.9 | 77.4±6.6 | 0.482 |
| ||||||
V30 (%) | 38.1±10.6 | 22.2±9.2 | 0.001 |
49.7±9.8 | 46.9±9.6 | 0.359 |
| ||||||
V45 (%) | 16.1±10.8 | 6.1±5.3 | 0.001 |
27.3±10.2 | 21.7±8.6 | 0.035 |
| ||||||
V60 (%) | 1.0±1.1 | 0.3±0.9 | 0.074 | 8.8±6.6 | 5.3±5.0 | 0.012 |
| ||||||
Dmean (Gy) | 27.8±4.1 | 20.7±3.2 | 0.001 |
32.4±4.5 | 30.5±3.7 | 0.105 |
| ||||||
Dmax (Gy) | 60.1±5.9 | 56.6±6.0 | 0.037 |
67.4±2.3 | 65.6±3.3 | 0.005 |
Values are presented as mean±standard deviation. Dmax, maximum dose; Dmean, mean dose, M-OC/OP, the mucosa of the oral cavity and oropharynx; M-tongue, mucosa of the tongue; SCTID, semi-customized tongue immobilization device; SMP, standard mouthpiece; VD (15, 30, 45, and 60), the percentage of the tongue volume that received D (15, 30, 45, and 60) Gy or more.
a)Statistically significant.
Comparison of dosimetric characteristics between the SMP and the SCTID for planning targets and OARs
Parameter | SMP | SCTID | p-value |
---|---|---|---|
P-GTV | |||
D2% (Gy) | 68.7±0.5 | 68.9±0.6 | 0.087 |
D98% (Gy) | 66.4±0.2 | 66.2±0.2 | 0.005 |
D50% (Gy) | 67.7±0.4 | 67.7±0.3 | 0.619 |
HI | 0.035±0.1 | 0.039±0.1 | 0.011 |
CI | 0.7±0.1 | 0.7±0.1 | 0.380 |
P-CTV | |||
D2% (Gy) | 68.3±0.4 | 68.4±0.4 | 0.570 |
D98% (Gy) | 58.5±2.2 | 58.4±2.5 | 0.430 |
D50% (Gy) | 62.9±2.4 | 62.9±2.6 | 0.912 |
HI | 0.2±0.1 | 0.2±0.1 | 0.286 |
CI | 0.8±0.1 | 0.8±0.1 | 0.742 |
Parotid glands | |||
Dmean (Gy) | 30.8±3.9 | 30.7±3.0 | 0.779 |
P-cord | |||
Dmax (Gy) | 30.6±4.9 | 30.5±7.4 | 0.973 |
Brainstem | |||
Dmax (Gy) | 40.8±12.7 | 40.2±11.6 | 0.624 |
Values are presented as mean±standard deviation. CI, conformity index; Dmax, maximum dose, Dmean, mean dose; DV%, minimum dose received by 2% (D2%), 98% (D98%), and 50% (D50%) of the PTVs; HI, homogeneity index; OARs, organ at risks; P-cord, planning spinal cord; P-CTV, planning clinical target volume; P-GTV, planning gross target volume; SCTID, semi-customized tongue immobilization device; SMP, standard mouthpiece.
a)Statistically significant.
Comparison of dosimetric characteristics between the planned dose and the accumulated adaptive dose with SCTID
Parameter | Tongue | Base of tongue | ||||
---|---|---|---|---|---|---|
|
| |||||
Planned dose | Accumulated adaptive dose | p-value | Planned dose | Accumulated adaptive dose | p-value | |
V15 (%) | 37.6±22.0 | 36.2±23.1 | 0.268 | 64.0±30.0 | 61.4±30.2 | 0.204 |
| ||||||
V30 (%) | 7.1±6.0 | 6.6±6.5 | 0.456 | 21.9±19.1 | 20.6±21.8 | 0.626 |
| ||||||
V45 (%) | 4.5±4.3 | 4.2±4.9 | 0.819 | 15.2±15.4 | 14.6±18.3 | 0.456 |
| ||||||
V60 (%) | 1.7±2.5 | 1.8±2.9 | 0.364 | 6.7±10.6 | 7.4±12.5 | 0.363 |
| ||||||
Dmean (Gy) | 0.3±0.7 | 0.4±0.9 | 0.268 | 1.4±3.6 | 1.8±4.6 | 0.579 |
| ||||||
Dmax (Gy) | 15.2±4.7 | 14.9±4.9 | 0.272 | 21.8±8.9 | 21.3±9.5 | 0.263 |
Values are presented as mean±standard deviation. Dmax, maximum dose; Dmean, mean dose; SCTID, semi-customized tongue immobilization device; VD (15, 30, 45, and 60), the percentage of the tongue volume that received D (15, 30, 45, and 60) Gy or more.
CCRT, concurrent chemoradiation therapy; NOS, not otherwise indicated; NPX, nasopharynx; RT, radiation therapy.
Dmax, maximum dose; Dmean, mean dose; DV, D dose delivered to V% of organ volume; M-OC/OP, mucosa of the oral cavity and oropharynx; M-tongue, mucosa of the tongue; P-cord, planning spinal cord; P-CTV, planning clinical target volume; P-GTV, planning gross target volume; VD, absolute or percentage of organ volume receiving D Gy or higher. P-cord means the planning volume for the spinal cord which was generated by adding 3–5 mm margin to the actual spinal cord.
Values are presented as mean±standard deviation. Dmax, maximum dose; Dmean, mean dose, M-OC/OP, the mucosa of the oral cavity and oropharynx; M-tongue, mucosa of the tongue; SCTID, semi-customized tongue immobilization device; SMP, standard mouthpiece; VD (15, 30, 45, and 60), the percentage of the tongue volume that received D (15, 30, 45, and 60) Gy or more. Statistically significant.
Values are presented as mean±standard deviation. CI, conformity index; Dmax, maximum dose, Dmean, mean dose; DV%, minimum dose received by 2% (D2%), 98% (D98%), and 50% (D50%) of the PTVs; HI, homogeneity index; OARs, organ at risks; P-cord, planning spinal cord; P-CTV, planning clinical target volume; P-GTV, planning gross target volume; SCTID, semi-customized tongue immobilization device; SMP, standard mouthpiece. Statistically significant.
Values are presented as mean±standard deviation. Dmax, maximum dose; Dmean, mean dose; SCTID, semi-customized tongue immobilization device; VD (15, 30, 45, and 60), the percentage of the tongue volume that received D (15, 30, 45, and 60) Gy or more.